Space instruments, such as satellites, are usually equipped with a certain number of deployable lengthening pieces, such as solar generators, antenna reflectors, poles, etc. Throughout the satellite launching phase, these lengthening pieces are kept in a folded back position so as to firstly reduce the spatial requirement, and secondly avoiding damaging them. The keeping of the lengthening pieces in this folded back position in ensured by stacking devices constituted, for example, by bolts traversing the various panels constituting each solar generator.
When the satellite is placed into orbit, pyrotechnic shears are triggered so as to cut the stacking bolts and free the solar generators or any similar lengthening pieces. The actual deployment is then ensured by elastic members mounted on hinges which each connect the panels of the solar generator.
In conventional joints, these elastic means are constituted by torsion springs which exert between adjacent panels a relatively high deployment torque. So as to ensure that too large shocks do not occur at the end of deployment, the deployment speed of the panels is therefore adjusted, most frequently by synchronizing the deployment of the various panels constituting the solar generators, as shown in particular in the document FR-A-2 371 343.
The document FR-A-2 635 077 describes a different type of joint in which the elastic means are constituted by preformed elastic strips with an arc of a circle section which generate a known deployment torque and which may be relatively slight. Furthermore, any friction is virtually eliminated by the fact that the joint includes two braces which roll off onto each other by being guided by flexible metallic plates on which a traction prestressing is exerted.
The original design of this latter joint generally makes it possible to suppress any system for regulating the deployment speed and synchronization of deployment of the various panels in relation to one another. However, in the case of large solar generators needing to support, once deployed, orbital torques requiring a particularly high minimum rigidity, the absence of any regulation and synchronization may result in an extremely high shock (corresponding, for example, to a torque of 220 Nm) when locking the panels at the end of deployment. In fact, the forces generated at the time of locking are that much more significant when the rigidity of the deployed lengthening piece is high. If it is too high, this locking shock may damage the lengthening piece and render it unusable.